Airborne ammonia in animal facilities is detrimental to the health of both the animals and the farm workers. The gas results from the decomposition of animal wastes, and its formation is influenced by litter moisture, pH, and temperature. Thus, the main factors affecting the levels of ammonia in animal facilities are the litter conditions and the amount of ventilation. Litter amendments have been developed that acidify the litter and inhibit ammonia volatilization. For example, dry alum (aluminum sulfate) provides excellent ammonia control (i.e., acidifies the litter and suppresses ammonia volatilization), but has the drawback that it requires adequate litter moisture and time for activation. Other litter treatments contain sulfuric acid, which provides immediate acidification and ammonia control without an activation step, but the ammonia control is short lived. Dry litter amendments are less hazardous to handle and easier to apply than liquid litter amendments. What is needed, therefore, is a dry litter amendment that provides both immediate and extended ammonia control.